A fluidistor which satisfies the aforementioned desideratum is provided upstream of the control chambers with a nozzel, normally in the form of a constriction of a passage defined by edges, and forms downstream of the control chambers a first region within which the flow lies either on one side or the other in dependence upon the pressure conditions and flow conditions prevailing in the fluidistor circuit. This region is often called the outlet-passage region since there is normally provided downstream of the control chambers in the fluidistor a wedge or stream-divider which defines these outlet passages. Every fluidistor exhibits a further region located downstream of the first region. Without the provision of such wedges in a fluidistor, that side of the stream of fluid remote from the wall portion in this region is broken up. When the fluidistor is provided with such wedges, the two streams of fluid are mixed on respective sides of the stream-divider in said region, immediately when switching occurs from one outlet passage to the other, to form a jet.